Dipyridamole and dobutamine-atropine stress echocardiography in the diagnosis of coronary artery disease. Comparison with exercise stress test, analysis of agreement, and impact of antianginal treatment

Multiple Phenotypes of Chronic Coronary Syndromes Identified by ABCDE Stress Echocardiography

BACKGROUND

Regional wall motion abnormality is considered a sensitive and specific marker of ischemia during stress echocardiography (SE). However, ischemia is a multifaceted entity associated with either coronary artery disease (CAD) or angina with normal coronary arteries, a distinction difficult to make using a single sign. The aim of this study was to evaluate the diagnostic potential of the five-step ABCDE SE protocol for CAD detection.

METHODS

From the 2016-2022 Stress Echo 2030 study data bank, 3,229 patients were selected (mean age, 66 ± 12 years; 2,089 men [65%]) with known CAD (n = 1,792) or angina with normal coronary arteries (n = 1,437). All patients were studied using both the ABCDE SE protocol and coronary angiography, within 3 months. In step A, regional wall motion abnormality is assessed; in step B, B-lines and diastolic function; in step C, left ventricular contractile reserve; in step D, coronary flow velocity reserve in the left anterior descending coronary artery; and in step E, heart rate reserve.

RESULTS

SE response ranged from a score of 0 (all steps normal) to a score of 5 (all steps abnormal). For CAD, rates of abnormal results were 347 for step A (19.4%), 547 (30.5%) for step B, 720 (40.2%) for step C, 615 (34.3%) for step D, and 633 (35.3%) for step E. For angina with normal coronary arteries, rates of abnormal results were 81 (5.6%) for step A, 429 (29.9%) for step B, 432 (30.1%) for step C, 354 (24.6%) for step D, and 445 (31.0%) for step E. The dominant "solitary phenotype" was step B in 109 patients (9.1%).

CONCLUSIONS

Stress-induced ischemia presents with a wide range of diagnostic phenotypes, highlighting its complex nature. Using a comprehensive approach such as the advanced ABCDE score, which combines multiple markers, proves to be more valuable than relying on a single marker in isolation.

Clinical judgement in chest pain: a case report

Background

Cardiac stress testing is a validated diagnostic tool to assess symptomatic patients with intermediate pretest probability of coronary artery disease (CAD). However, in some cases, the cardiac stress test may provide inconclusive results and the decision for further workup typically depends on the clinical judgement of the physician. These decisions can greatly affect patient outcomes.

Case presentation

We present an interesting case of a 54-year-old Caucasian male with history of tobacco use and gastroesophageal reflux disease (GERD) who presented with atypical chest pain. He had an asymptomatic electrocardiogram (EKG) stress test with intermediate probability of ischemia. Further workup with coronary computed tomography angiography (CCTA) and cardiac catheterization revealed multivessel CAD requiring a bypass surgery. In this case, the patient only had a history of tobacco use but no other significant comorbidities. He was clinically stable during his hospital stay and his testing was anticipated to be negative. However to complete workup, cardiology recommended anatomical testing with CCTA given the indeterminate EKG stress test results but the results of significant stenosis were surprising with the patient eventually requiring coronary artery bypass grafting (CABG).

Conclusion

As a result of the availability of multiple noninvasive diagnostic tests with almost similar sensitivities for CAD, physicians often face this dilemma of choosing the right test for optimal evaluation of chest pain in patients with intermediate pretest probability of CAD. Optimal test selection requires an individualized patient approach. Our experience with this case emphasizes the role of history taking, clinical judgement, and the risk/benefit ratio in deciding further workup when faced with inconclusive stress test results. Physicians should have a lower threshold for further workup of patients with inconclusive or even negative stress test results because of the diagnostic limitations of the test. Instead, utilizing a different, anatomical test may be more valuable. Specifically, the case established the usefulness of CCTA in cases such as this where other CAD diagnostic testing is indeterminate.

Accuracy and Prognostic Value of Physiologist-Led Stress Echocardiography for Coronary Disease

BACKGROUND

We demonstrated that physiologist-led stress echocardiography (PLSE) is feasible for coronary artery disease (CAD) assessment. We sought to extend our work by assessing its accuracy and prognostic value.

METHODS

Retrospective study of 898 subjects undergoing PLSE (n=393) or cardiologist-led stress echocardiography (CLSE) (n=505) for CAD assessment using exercise or dobutamine. For accuracy assessment, the primary outcome was the ability of stress echocardiography to identify significant CAD on invasive coronary angiography (ICA). Incidence of 24-month non-fatal MI, total and cardiac mortality, revascularisation and combined major adverse cardiac events (MACE) were assessed.

RESULTS

Demographics, comorbidities, CAD predictors, CAD pre-test probability and cardiac medications were matched between the PLSE and CLSE groups. PLSE had high sensitivity, specificity, positive and negative predictive value and accuracy (85%, 74%, 69%, 88%, 78% respectively). PLSE accuracy measures were similar and non-inferior to CLSE. There was a similar incidence of individual and combined outcomes in PLSE and CLSE subjects. Negative stress echocardiography conferred a comparably low incidence of non-fatal MI (PLSE 1.4% vs. CLSE 0.9%, p=0.464), cardiac mortality (0.6% vs. 0.0%, p=0.277) and MACE (6.8% vs. 3.1%, p=0.404).

CONCLUSION

This is the first study of the accuracy compared with gold standard of ICA, and prognostic value of PLSE CAD assessment. PLSE demonstrates high and non-inferior accuracy compared with CLSE for CAD assessment. Negative PLSE and CLSE confer a similarly very low incidence of cardiac outcomes, confirming for the first time the important prognostic value of PLSE.

Comparison of two dipyridamole infusion protocols for myocardial perfusion imaging in subjects with low likelihood of significant obstructive coronary artery disease

BACKGROUND

Myocardial perfusion imaging (MPI) with positron emission tomography allows accurate measurements of myocardial blood flow (MBF). Stress MBF thresholds have been proposed to provide diagnostic and prognostic information in different pathology. Most studies relying on dipyridamole use a 5-minute infusion protocol, while current guidelines recommend a 4-minute infusion. The purpose of this study is to compare the effects of different dipyridamole infusion times on stress MBF.

METHODS

The charts of 2,207 patients who underwent rubidium-82 MPI were retrospectively reviewed and 147 subjects with low likelihood of significant coronary artery disease (CAD) defined as calcium score = 0, body mass index < 45 kg·m-2, and summed stress score ≤ 3 were included. Of those, 65 were imaged with a 4-minute dipyridamole infusion (0.56 mg·kg-1) protocol and 82 with a 5-minute protocol (0.70 mg·kg-1).

RESULTS

Stress MBF (3.23±0.76 vs 3.02±0.71 mL·min-1·g-1, P = 0.09), myocardial flow reserve (2.70±0.67 vs 2.85±0.74, P = 0.20), and coronary vascular resistance index (30±10 vs 31±9 mmHg × g × min·mL-1, P = 0.38) were not significantly different between the two protocols. The 5-minute protocol was associated with higher prevalence of symptoms (92.7% vs 81.5%, P = 0.04) and greater decrease in systolic blood pressure (- 9 vs - 6 mmHg, P = 0.03).

CONCLUSIONS

The 4-minute and 5-minute dipyridamole infusion protocols produce comparable myocardial flow response, hemodynamic changes, and symptoms, in subjects with low likelihood of significant obstructive CAD.

Intracranial hemorrhage as a complication of dobutamine stress echocardiography: case report and review of the literature

Dobutamine stress echocardiography is a generally well-tolerated study to evaluate patients with suspected coronary artery disease. Rare but life-threatening complications of this study have been well described. Severe hypertensive responses are a known but uncommon adverse reaction to dobutamine infusion. The authors report a case of intracranial hemorrhage in the setting of severe hypertension as a complication of dobutamine stress echocardiography. The patient was on systemic anticoagulation with warfarin for a prosthetic mitral valve and had an international normalized ratio (INR) of 3.8 that was slightly over the therapeutic goal INR of 2.5-3.5. He had no predisposing intracranial lesions such as tumor, vascular malformation, or aneurysm. He suffered an intraparenchymal hemorrhage in three distinct areas of his brain. Intracranial hemorrhage related to dobutamine infusion has not been reported previously, but given the known risk of hypertension, life-threatening sequelae including intracranial hemorrhage are possible.

Frequency and characteristics of myocardial ischemia recorded during stress echocardiography in patients with high coronary risk

BACKGROUND/AIM

Ischemic heart disease is the major cause of morbidity and mortality in the world as well as in our country. Ischemic heart disease has the multifactorial origin and the presence of several risk factors increases the risk of myocardial ischemia. The aim of the study was to evaluate the frequency and characteristics of myocardial ischemia in asymptomatic subjects with two or more risk factors for coronary artery disease during stress echocardiography.

METHODS

In 240 high risk asymptomatic subjects (an absolute risk of fatal cardiovascular disease of more than 5%, according to the Systemic Coronary Risk Evaluation Chart), the exercise stress echocardiography test was performed. The criterion for myocardial ischemia was the appearance of transient segmental wall motion abnormality (WMA). The wall motion score index was calculated before and after the exercise stress echocardiography.

RESULTS

During exercise stress echocardiography, in 36 (15%) subjects WMA occurred. Out of 36 subjects with myocardial ischemia, in 10 (27.8%) subjects WMA and ST segment depression were accompanied with the first occurrence of chest pain (the subgroup with symptomatic myocardial ischemia), in 20 (55.6%) subjects WMA and ST segment depression were detected and in 6 (16.6%) subjects only WMA occurred (the subgroup with silent myocardial ischemia). There were no significant differences between the subgroups with symptomatic and silent myocardial ischemia with regard to exercise tolerance, heart rate at the onset of WMA, and time to the onset of WMA, but the wall motion score index was significantly higher in the subjects with symptomatic myocardial ischemia (p < 0.01). In all the individuals with symptomatic myocardial ischemia, significant stenosis of the coronary arteries was found by coronary angiography. Out of 26 subjects with asymptomatic myocardial ischemia, coronary angiography was performed in 18 and significant stenosis of the coronary arteries was diagnosed in all of them. The number and grade of coronary stenosis in subjects with symptomatic and silent myocardial ischemia were similar.

CONCLUSION

The obtained results presented the incidence of myocardial ischemia in 15% of asymptomatic subjects with high coronary risk during stress echocardiography. Silent myocardial ischemia was markedly more frequent than symptomatic one, but in the subjects with symptomatic ischemia, the wall motion score index was significantly higher.

Methodological Analysis of Diagnostic Dobutamine Stress Echocardiography Studies

BACKGROUND

Dobutamine stress echocardiography (DSE) is an accepted test for the diagnosis of coronary artery disease (CAD), despite its wide diagnostic accuracy.

AIM

Which factors cause test variability of DSE for the diagnosis of CAD.

METHODS

In a retrospective analysis of 46 studies in 5,353 patients, the potential causes of diagnostic variability were systematically analyzed, including patient selection, definition of CAD, chest pain characteristics, confounding factors for DSE (left ventricular hypertrophy, left bundle branch block, female gender), work-up bias (present when patient's chance to undergo coronary angiography is influenced by the result of DSE), review bias (present when DSE is interpreted in relation to CAG), DSE protocol and definition of a positive DSE.

RESULTS

Diagnostic variability was related to definition of a positive test, but not related to the definition of CAD or DSE protocol. However, only three of eight methodological standards for research design found general compliance. Differences in the selection of the study population (quality of echocardiographic window, angina pectoris), handling of confounding factors and analysis of disease in individual coronary arteries were observed. Lack of data on analysis of relevant chest pain syndromes and handling of nondiagnostic test results hampered further evaluation of these standards.

CONCLUSION

Methodological problems may explain the wide range in diagnostic variability of DSE. An improvement of clinical relevance of DSE testing is possible by stronger adherence to common and new methodological standards.

Factors affecting sensitivity and specificity of diagnostic testing: dobutamine stress echocardiography

BACKGROUND

Clinical characteristics of patients, angiographic referral bias, and several technical factors may all affect the reported diagnostic accuracy of tests. The aim of this study was to assess their influence on the diagnostic accuracy of dobutamine stress echocardiography (DSE).

METHODS

The medical literature from 1991 to 2006 was searched for diagnostic studies using DSE and meta-analysis was applied to the 62 studies thus retrieved, including 6881 patients. These studies were analyzed for patient characteristics, angiographic referral bias, and several technical factors.

RESULTS

The sensitivity of DSE was significantly related to the inclusion of patients with prior myocardial infarctions (0.834 vs 0.740, P < .01) and defining the results of DSE as already positive in case of resting wall motion abnormalities rather than obligatory myocardial ischemia (0.786 vs 0.864, P < .01). Specificity tended to be lower when patients with resting wall motion abnormalities were included in a study (0.812 vs 0.877, P < .10). The presence of referral bias adversely affected the specificity of DSE (0.771 vs 0.842, P < .01).

CONCLUSION

This analysis suggests that the reported sensitivity of DSE is likely higher and the specificity lower than expected in routine clinical practice because of the inappropriate inclusion of patients with prior myocardial infarctions, the definition of positive results on DSE, and the negative influence of referral bias. However, in the patient subset that will be sent to coronary angiography, the opposite results can be expected.

Detection of single-vessel coronary artery disease by dipyridamole stress echocardiography: no longer a problem?

We aimed to evaluate whether addition of myocardial contrast echocardiography (MCE) perfusion data improves the sensitivity of stress echocardiography for detection of single-vessel coronary artery disease (svCAD) and to compare the diagnostic value of MCE and single-photon emission computed tomography (SPECT) for detection of svCAD.

METHODS

One hundred and three patients with suspected or known stable CAD underwent dipyridamole (0.84 mg kg(-1) intravenously over 4 min)-atropine (up to 1 mg intravenously) stress echocardiography combined with MCE. Wall motion abnormalities (WMA) and perfusion defects were assessed visually. Presence of CAD was detected by coronary angiography.

RESULTS

Single-vessel coronary artery disease defined as >or=70% stenosis was detected in 30% of patients, whereas 26% of patients had svCAD defined as >or=50% stenosis. Presence of inducible WMA had 35% and 26% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. Concomitant evaluation of MCE increased the sensitivity to 74% (P = 0.005) and 56% (P = 0.053), respectively, using any inducible abnormality (WMA or perfusion defects) as a criterion. Presence of any (inducible or fixed) WMA had 77% and 59% sensitivity for detection of svCAD defined as >or=70% and >or=50% stenosis, respectively. In case of such criterion for stress test positivity, the improvement in sensitivity provided by addition of MCE (to 94% and 78%, respectively) did not reach statistical significance.

CONCLUSIONS

Addition of MCE perfusion analysis during stress echocardiographical examination based on evaluation of inducible abnormalities improves the test sensitivity for detection of svCAD. This benefit is less apparent when fixed WMA and perfusion defects are incorporated into the stress test positivity criterion.

The prognostic value of Doppler echocardiographic-derived coronary flow reserve is not affected by concomitant antiischemic therapy at the time of testing

BACKGROUND

When wall motion abnormality is the diagnostic end point, concomitant antiischemic therapy heavily modulates the prognostic value of dipyridamole echocardiography test (DET). A negative test result is less benign, and a positive test result is more malignant if performed under therapy. Recently, coronary flow reserve (CFR) was added to wall motion in dual imaging DET. The aim of the study was to determine whether antianginal medications affect the prognostic value of Doppler echocardiographic-derived CFR in patients with known or suspected coronary artery disease undergoing DET.

METHODS

In a prospective, multicenter, observational study, we evaluated 1,779 patients (1,072 males; 64 +/- 11 years) who underwent high-dose dipyridamole (0.84 mg/kg for 6 minutes) stress echo with CFR evaluation of left anterior descending (LAD) artery by Doppler.

RESULTS

Seven hundred thirty-three (41%) patients were on antiischemic therapy at time of testing (nitrates and/or calcium antagonists and/or beta-blockers). Mean CFR was 2.3. +/- 0.6. At individual patient analysis, 1,141 patients had normal (CFR >2.0) and 638 had abnormal (CFR <or=2.0) CFR on LAD. During a median follow-up of 36 months, 263 events occurred as follows: 36 deaths and 59 ST-elevation myocardial infarctions (STEMIs) and 168 non-STEMIs (NSTEMIs). Survival was highest in patients with normal CFR and lowest in patients with abnormal CFR (87% vs 34%, P = .0001). Survival was comparable in patients with normal CFR on and off therapy and in patients with abnormal CFR on and off therapy. At multivariable analysis, hypertension (hazard ratio [HR] 1.5, 95% CI 1.0-1.9, P = .010), DET positivity for regional wall motion abnormalities (HR 5.7, 95% CI 4.3-7.4, P = .000), an abnormal CFR on LAD (HR 3.3, 95% CI 2.5-4.4, P = .000) were independent prognostic predictors of hard cardiac events.

CONCLUSION

Ongoing antiischemic therapy at the time of testing does not modulate the prognostic value of Doppler echocardiographic-derived coronary flow reserve.

The diagnostic accuracy of pharmacological stress echocardiography for the assessment of coronary artery disease: a meta-analysis

BACKGROUND

Recent American Heart Association/American College of Cardiology guidelines state that "dobutamine stress echo has substantially higher sensitivity than vasodilator stress echo for detection of coronary artery stenosis" while the European Society of Cardiology guidelines and the European Association of Echocardiography recommendations conclude that "the two tests have very similar applications". Who is right?

AIM

To evaluate the diagnostic accuracy of dobutamine versus dipyridamole stress echocardiography through an evidence-based approach.

METHODS

From PubMed search, we identified all papers with coronary angiographic verification and head-to-head comparison of dobutamine stress echo (40 mcg/kg/min +/- atropine) versus dipyridamole stress echo performed with state-of-the art protocols (either 0.84 mg/kg in 10' plus atropine, or 0.84 mg/kg in 6' without atropine). A total of 5 papers have been found. Pooled weight meta-analysis was performed.

RESULTS

the 5 analyzed papers recruited 435 patients, 299 with and 136 without angiographically assessed coronary artery disease (quantitatively assessed stenosis > 50%). Dipyridamole and dobutamine showed similar accuracy (87%, 95% confidence intervals, CI, 83-90, vs. 84%, CI, 80-88, p = 0.48), sensitivity (85%, CI 80-89, vs. 86%, CI 78-91, p = 0.81) and specificity (89%, CI 82-94 vs. 86%, CI 75-89, p = 0.15).

CONCLUSION

When state-of-the art protocols are considered, dipyridamole and dobutamine stress echo have similar accuracy, specificity and - most importantly - sensitivity for detection of CAD. European recommendations concluding that "dobutamine and vasodilators (at appropriately high doses) are equally potent ischemic stressors for inducing wall motion abnormalities in presence of a critical coronary artery stenosis" are evidence-based.

Accelerated stress real-time myocardial contrast echocardiography for the detection of coronary artery disease: comparison with 99mTc single photon emission computed tomography

OBJECTIVE

The aims of this prospective study were to compare the diagnostic value of accelerated vasodilator stress real-time myocardial contrast echocardiography (MCE) and single photon emission computed tomography (SPECT) against coronary angiography and to evaluate whether the addition of MCE perfusion data improves the diagnostic accuracy of stress echocardiography.

METHODS

A total of 103 patients with suspected or known stable coronary artery disease (CAD) underwent SPECT and accelerated high-dose dipyridamole (0.84 mg/kg intravenously for 4 minutes) atropine (up to 1 mg intravenously) stress real-time qualitative MCE. The presence of CAD was detected by coronary angiography.

RESULTS

CAD defined as >or= 70% stenosis was detected in 77% of patients, whereas 86% of patients had CAD defined as >or= 50% stenosis. In a territory-by-territory analysis, the concordance between MCE and SPECT in detecting perfusion defects varied from 72.8% (kappa = 0.386) to 89.3% (kappa = 0.642). There were no significant differences between MCE and SPECT in sensitivity, specificity, and diagnostic accuracy for identifying patients with CAD. Combining MCE and wall motion abnormality analysis significantly improved the sensitivity of the test compared with wall motion abnormality analysis alone.

CONCLUSIONS

Accelerated vasodilator stress real-time MCE yields a good concordance with SPECT in detection of perfusion defects and a similar diagnostic value for the detection of CAD. The addition of MCE perfusion data improves the diagnostic value of stress echocardiography.

Ischemia induced by transesophageal atrial pacing stress echocardiography predicts long-term mortality

OBJECTIVES

It was the aim of this study to investigate the long-term value of transesophageal atrial pacing in predicting death in patients with known or suspected coronary artery disease.

BACKGROUND

Exercise, dobutamine and dipyridamole stress echocardiography are all effective in predicting cardiac death. Transesophageal atrial pacing stress echocardiography (TAPSE) is a safe alternative to pharmacologic tests, but no information is available on prognosis with TAPSE.

METHODS

One thousand and ten TAPSE were performed in 975 consecutive patients. TAPSE was feasible in 970 tests (96%); after exclusion of the 35 patients with more than 1 TAPSE and those 42 lost at follow-up (mean 4.5 +/- 3.7 years, median 6 years), the final population consisted of 857 patients (675 males, 58 +/- 9 years old). The Cox model was used to analyze the association of clinical, resting and TAPSE variables with cardiac death.

RESULTS

TAPSE was abnormal in 281 (32%) patients. There were 46 cardiac-related deaths (5%), 25 among the 281 patients with an abnormal test (8.9%) and 21 among the 576 patients with a normal test (3.6%). The predictors of cardiac death were age, previous revascularization, resting wall motion score index and its variation during TAPSE. Abnormal TAPSE significantly increases the value of models predicting cardiac death. Moreover, cardiac mortality increased progressively with the extent of the induced ischemia.

CONCLUSIONS

TAPSE is a useful tool in predicting death in patients with known or suspected coronary artery disease and might be considered an alternative to pharmacologic stressors.

Safety and Predictors of Complications with a New Accelerated Dobutamine Stress Echocardiography Protocol

BACKGROUND

This study sought to document the safety of a new accelerated dobutamine-atropine stress echocardiography protocol and to analyze its complications.

METHODS

Dobutamine-atropine stress echocardiography studies were performed using an incremental dobutamine infusion protocol from 20 to 40 microg/kg/min in 3-minute stages and followed by atropine.

RESULTS

A total of 962 patients were included. Mean age was 64 +/- 11 years and 584 were male (61%). Mean ejection fraction was 62 +/- 10%. Complications included hypertensive responses in 66 patients (7%), arrhythmias in 26 (2.7%), and symptomatic hypotension in 16 (1.7%). No patient developed heart failure, acute myocardial infarction, ventricular fibrillation, or died. The independent predictors of hypertensive responses were age, baseline systolic blood pressure, and treatment with nitrates. The independent predictors of arrhythmias were history of hypertension, previous coronary artery disease, and baseline heart rate.

CONCLUSIONS

This accelerated dobutamine-atropine stress echocardiography protocol is safe in a low-risk population and has a rate of complications similar to that reported for the standard protocol.

Additional prognostic value of coronary flow reserve in diabetic and nondiabetic patients with negative dipyridamole stress echocardiography by wall motion criteria

OBJECTIVES

The aim of this prospective, multicenter, observational study was to compare the prognostic value of Doppler echocardiographic-derived coronary flow reserve (CFR) in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography.

BACKGROUND

The prognostic value of CFR in diabetic patients with negative stress echocardiography remains unknown.

METHODS

The study group consisted of 1,130 patients (207 diabetics) with known (n = 418) or suspected (n = 712) coronary artery disease and negative stress echocardiography by wall motion criteria. All underwent dipyridamole (up to 0.84 mg/kg over 6 min) echocardiography with CFR evaluation of left anterior descending artery by Doppler. A value of CFR < or =2.0 was considered abnormal.

RESULTS

Coronary flow reserve was abnormal in 309 (27%) patients. During a median follow-up of 16 months, 98 events (8 deaths, 24 ST-segment elevation myocardial infarctions, and 66 non-ST-segment elevation myocardial infarctions) occurred. In addition, 101 patients underwent revascularization and were censored. Multivariable prognostic indicators were abnormal CFR (p < 0.0001), anti-ischemic therapy at the time of testing (p = 0.002), age (p = 0.02), and resting wall motion abnormality (p = 0.05). The event rate was markedly higher (p < 0.0001) for both diabetic and nondiabetic patients with abnormal CFR as compared with diabetic and nondiabetic patients with normal CFR. Of note, a preserved CFR off therapy identified diabetic and nondiabetic patients with better survival and comparable yearly event rates (2.2% vs. 2.0%, p = 0.80).

CONCLUSIONS

Coronary flow reserve provides independent prognostic information in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography. In particular, a normal CFR off therapy is associated with better and similar survival in the 2 populations.

Tolerability and infusion time of an accelerated infusion dobutamine echocardiography protocol

OBJECTIVES

A new, accelerated dobutamine-atropine stress echocardiography (DASE) protocol (baseline 20 mcg/kg/min; 40 mcg/kg/min) was compared with a standard protocol in patients with suspected coronary artery disease (CAD) to evaluate tolerability, length of infusion, and overall test times, as well as safety.

METHODS

Patients received the DASE or the standard protocol on an alternating basis (n = 164).

RESULTS

Total test time, including patient recovery (HR < 100 bpm), dropped from an average of 19:23-12:12 min (p < 0.0001). Average symptom duration decreased from 5:50 to 3:17 min (p < 0.01). Women had shorter total test times in both accelerated and standard protocols compared to that of men.

CONCLUSIONS

The accelerated DASE protocol is a well tolerated alternative to standard dobutamine stress testing allowing practitioners to reduce test times without increasing the incidence of arrhythmias. Patients in the accelerated arm also had shorter duration of symptoms.

Dobutamine stress echocardiography in the diagnosis of coronary artery disease in women with chest pain: comparison with different noninvasive tests

BACKGROUND

Diagnosis of coronary artery disease(CAD) in women remains elusive. The classical diagnostic armamentarium has been found to be very limited. Dobutamine stress echocardiography has emerged as a powerful test in assessing CAD in the general population, but most studies failed to include women.

HYPOTHESIS

The accuracy of dobutamine stress echocardiography in the diagnosis of CAD in women with chest pain is high and superior to dipyridamole echocardiography, exercise electrocardiography, and sestamibi single-photon emission tomography (MIBI-SPECT) scintigraphy.

METHODS

We studied 99 consecutive women with chest pain and no previous history of CAD who underwent dobutamine echocardiography and coronary angiography. We also compared these results with those of dipyridamole echocardiography in 63 patients. exercise stress testing in 83 (48 conclusive), and MIBI-SPECT scintigraphy during dobutamine infusion in 54.

RESULTS

Significant CAD was found in 42 women. Sensitivity and specificity of dobutamine stress echocardiography were 69 and 89%, respectively. Dipyridamole echocardiography showed similar accuracy (sensitivity 72% and specificity 94%). Finally, sensitivity of exercise test and MIBI-SPECT was similar (76 and 88%, respectively) and specificity was lower (53 and 57%, respectively). After excluding patients known to have a high incidence of false positive results, MIBI-SPECT specificity rose up to 80%.

CONCLUSION

Dobutamine stress echocardiography and dipyridamole echocardiography bear a high diagnostic accuracy in women with chest pain. MIBI-SPECT is also a useful tool after excluding subgroups with a high incidence of false positive results.

Incremental diagnostic value of ultrasonographic assessment of coronary flow reserve with high-dose dipyridamole in patients with acute coronary syndrome

BACKGROUND

Coronary flow reserve (CFR) assessment by transthoracic Doppler echocardiography has been found to be useful in subjects with suspected coronary artery disease. An important clinical question is whether such technique can be successfully applied in patients admitted to the coronary care unit with an acute coronary syndrome to detect a significant left anterior descending (LAD) disease.

METHODS

One hundred fifty-nine patients with acute coronary syndrome (93 patients with unstable angina, 66 with acute inferior or lateral myocardial infarction) were included in the present analysis. Patients underwent a high-dose dipyridamole stress (0.84 mg/kg) with combined assessment of CFR in the LAD and regional wall motion. Blood flow velocities were recorded in the mid-distal portion of the LAD using a digital ultrasonographic system and CFR was calculated as the ratio of hyperemia-induced peak diastolic velocity to resting peak diastolic flow velocity. All patients underwent coronary angiography and a significant LAD stenosis was classified for lumen narrowing > or = 70%.

RESULTS

Adequate Doppler recordings in the LAD were obtained in 92% of patients. A contrast agent was used in the 39% of examinations. No major adverse reaction occurred in any patient. A receiving operating characteristic curve showed that a CFR value < 1.9 had a sensitivity of 85%, a specificity of 87%, a positive predictive value of 71%, a negative predictive value of 94% and a diagnostic accuracy of 86% for identifying a significant LAD stenosis. The area under the receiving operating characteristic curve computed for CFR was significantly higher than for wall motion score index (p < 0.001). In a stepwise forward, multiple logistic regression analysis, both CFR (OR = 4.8, 95% C.I. 3.7-5.3; p < 0.00001) and the wall motion score index for the LAD territory (OR = 4.2, 95% C.I. 2.6-6.8; p < 0.0001) were independent determinants of LAD stenosis > or = 70%.

CONCLUSION

Early assessment of CFR by transthoracic Doppler echocardiography is feasible and safe and provides additional information to identify subjects with acute coronary syndrome and significant LAD stenosis.

A meta-analytic comparison of echocardiographic stressors

BACKGROUND

The relative performance of alternative stressors for stress echocardiography for the diagnosis of coronary artery disease (CAD) is not well established.

METHODS

All studies published between 1981 to December 2001 who met inclusion criteria were included in this analysis. We performed a summary receiver operator characteristic (SROC) analysis and calculated weighted mean of the likelihood ratio and sensitivity/specificity. A covariate analysis using meta-regression methods was also performed.

RESULTS

Forty-four studies presented data on Exercise, 11 on Adenosine, 80 on Dobutamine, 40 on Dipyridamole, 16 on transatrial pacing transesophageal echocardiography (Tap-TEE), and 7 on transatrial pacing transthorasic echocardiography (Tap-TTE). SROC analysis showed that the following order of most discriminatory to least: Tap-TEE, Exercise, Dipyridamole, Dobutamine and Adenosine. Weighted means sensitivity/specificity were Exercise: 82.6/84.4%, Adenosine: 68.4/80.9%, Dobutamine: 79.6/85.1%, Dipyridamole: 71.0/92.2%, Tap-TTE: 90.7/86.1%, and Tap-TEE: 86.2/91.3%. Covariate analysis showed that the discriminatory power of Exercise decreased with increasing mean age.

CONCLUSIONS

Tap-TEE is a very accurate test for both ruling in and ruling out CAD although its invasiveness may limit its clinical acceptability. Exercise is a well-balanced satisfactory test for both ruling in and ruling out but performance might be lower for the elderly. Dobutamine offers a reasonable compromise for Exercise. Dipyridamole might be good for ruling in but not for ruling out CAD. The incapability in ruling-out CAD was a major problem in clinical application of the stress. Adenosine was the least useful stressor in diagnosing CAD.

The additional prognostic value of coronary flow reserve on left anterior descending artery in patients with negative stress echo by wall motion criteria. A Transthoracic Vasodilator Stress Echocardiography Study

BACKGROUND

Vasodilator stress echocardiography allows imaging of left anterior descending (LAD) coronary flow reserve (CFR), which may provide additional prognostic information over regional wall motion.

AIM

To assess the prognostic value of CFR in patients with known or suspected coronary artery disease (CAD) and negative stress echo.

METHODS

We studied 329 consecutive patients (193 men, age 61 +/- 13 years) with known (n = 101) or suspected (n = 228) CAD and negative stress echo by standard wall motion criteria. All patients underwent dipyridamole (up to 0.84 mg/kg in 10 minutes) stress echo with CFR evaluation of LAD by Doppler.

RESULTS

During follow-up (28 +/- 10 months), 22 events occurred: 1 cardiac death, 6 nonfatal myocardial infarctions, 5 unstable anginas, and 10 late (> 6 months) coronary revascularizations. Moreover, 9 patients underwent early (< 6 months) revascularization and were censored. Using a receiver operating characteristic analysis, CFR < or = 1.92 was the best predictor of future events (area under the curve = 0.80, sensitivity = 77%, specificity = 85%) and was taken as criterion for reduced CFR accordingly. Sixty-three (19%) patients had reduced and 266 (81%) had normal CFR on LAD. The 36-month event-free survival was higher in patients with normal and lower in patients with reduced CFR (98% vs 64%, P < .0001). At Cox analysis, CFR of LAD (hazard ratio [HR] 16.52, 95% CI 5.76-47.40, P < .0001), left ventricular mass index (HR 1.03 per unit increment, 95% CI 1.00-1.05, P = .01), and smoking habit (HR 3.00, 95% CI 1.24-7.23, P = .01) were independent prognostic indicators. Using an interactive stepwise procedure, CFR on LAD provided additional prognostic information to clinical, resting echo, and angiographic findings.

CONCLUSIONS

In patients with known or suspected CAD and negative stress echocardiography by wall motion criteria, CFR provides independent information for prognostic stratification, and a reduced CFR is associated with a less benign long-term outcome.

Anti-ischemic therapy and stress testing: pathophysiologic, diagnostic and prognostic implications

Anti-ischemic therapy, in particular beta-blockers, is the most commonly employed drug for the control of myocardial ischemia in patients with stable coronary artery disease. Its widespread use also in patients with suspected coronary artery disease has important practical, clinical diagnostic and prognostic implications because diagnostic tests are heavily influenced by its effects. In the present review, the pathophysiological mechanisms of ischemia protection by antianginal therapy are described. Not all stressors are created equal in front of the different classes of antianginal drugs and on their turn the different classes of drugs exert different levels of protection on inducible ischemia. Several clinical implications can be drawn: From the diagnostic viewpoint antianginal therapy decreases test sensitivity, offsetting the real ischemic burden for a too high percentage of false negative tests. From the prognostic viewpoint test positivity in medical therapy identifies a group of subjects at higher risk of experiencing cardiac death and positivity on medical therapy can be considered a parameter of ischemia severity. Nonetheless in patients with known coronary artery disease the ability of antianginal therapy to modify the ischemic threshold at stress testing represent a powerful means to assess therapy efficacy. From a practical viewpoint, the use of antianginal therapy at time of testing has advantages and disadvantages which are largely dependent on the purpose a test is performed: if the purpose of testing is to diagnose ischemia, it should be performed in the absence of antianginal medications. If the purpose of testing is to assess the protective effects of antianginal therapy, the test should be performed on medications.

Prognostic Value of Pharmacological Stress Echocardiography Is Affected by Concomitant Antiischemic Therapy at the Time of Testing

Background— The aim of this study was to determine whether antianginal medications affect the prognostic value of pharmacological stress echocardiography.

Methods and Results— From the EPIC-EDIC Data Bank, 7333 patients (5452 men; age; 59±10 years) underwent pharmacological stress echocardiography with either high-dose dipyridamole (0.84 mg/kg over 10 minutes; n=4984) or high-dose dobutamine (up to 40 μg · kg −1 · min −1 ; n=2349) (DET) for diagnostic purposes. At the time of testing, 1791 patients were on antiischemic therapy (nitrates and/or calcium antagonists and/or β-blockers). Patients were followed up for a mean of 2.6 years (range, 1 to 206 months). DET was positive for myocardial ischemia in 2854 patients (39%) and negative in 4479 (61%). Total mortality was 336 (4.5%). Death was attributed to cardiac causes in 161 patients (2.1%). Survival was highest in patients with negative DET off therapy and lowest in patients with positive DET studied on therapy (95% versus 81%; P =0.0000). Survival was comparable in patients with a negative test on therapy and in patients with a positive test off therapy (88% versus 84%, P =NS).

Conclusions— Ongoing antiischemic therapy at the time of testing heavily modulates the prognostic value of pharmacological stress echo. In the presence of concomitant antiischemic therapy, a positive test is more prognostically malignant, and a negative test less prognostically benign.

Simultaneous analysis of wall motion and coronary flow reserve of the left anterior descending coronary artery by transthoracic doppler echocardiography during dipyridamole stress echocardiography

BACKGROUND

Coronary flow reserve (CFR) can be measured in the left anterior descending artery (LAD) by dipyridamole transthoracic Doppler echocardiography (DTTDE). This information may critically improve the diagnostic accuracy of dipyridamole stress echocardiography, which is limited by moderate sensitivity.

OBJECTIVE

We sought to assess the feasibility and accuracy of value of DTTDE.

METHODS

We evaluated 752 consecutive patients (478 men; mean age, 64.7 years) referred for dipyridamole stress echocardiography. The diastolic velocity in the LAD was continuously monitored with pulsed Doppler at baseline and during hyperemia induced by the infusion of 0.84 mg/kg of dipyridamole. CFR was calculated as the ratio of maximal and basal diastolic velocity; a value < 2 was considered to indicate decreased CFR. Wall motion was assessed semiquantitatively. Coronary angiography was performed in 132 patients the week after DTTDE.

RESULTS

Adequate tracings were obtained in 95% of patients studied (715 of 752). In the subset of 132 patients undergoing coronary angiography, 71 patients (group A) showed a nonsignificant (<70%) and 61 patients (group B) a significant stenosis of the LAD. In group A, 65 had a normal wall-motion response (91.5% specificity) and 19 patients showed a decreased CFR (73.2% specificity; P =.1). In group B, new wall-motion abnormalities were seen in 42 patients (68.8% sensitivity), whereas CFR was decreased in 52 patients (86.8% sensitivity; P <.02).

CONCLUSION

Simultaneous assessment of wall motion and CFR of the LAD with DTTDE was highly feasible and safe. The information about CFR had a significantly higher sensitivity than the analysis of wall motion during dipyridamole stress echocardiography.

Dobutamine pharmacodynamics during dobutamine stress echocardiography and the impact of beta-blocker withdrawal: a report from the Women's Ischemic Syndrome Evaluation Study

STUDY OBJECTIVES

To determine the pharmacodynamic parameters of dobutamine during dobutamine stress echocardiography (DSE) and to determine how beta-blocker withdrawal the evening before DSE affects responses to dobutamine during DSE.

DESIGN

Retrospective analysis.

SETTING

University medical center.

PATIENTS

One hundred thirty-six women who had chest pain or other symptoms suggestive of myocardial ischemia and were considered to have a clinical indication for coronary angiography

MEASUREMENTS AND MAIN RESULTS

Patients underwent DSE with dobutamine dosages titrated from 5 to 40 microg/kg/minute. The infusion was terminated if the patient reached target heart rate or symptoms developed. Those taking beta-blockers withheld their doses the evening before DSE. Traditional pharmacodynamic modeling revealed a wide range in responses to dobutamine. Data for 62% of patients not taking beta-blockers were described by the Emax (maximum heart rate response to dobutamine) model, whereas data for only 39% of patients taking beta-blockers were best described by this model (p = 0.01). Patients taking beta-blockers also had a smaller mean increment in left ventricular ejection fraction (10.8% +/- 4.2% vs 14.1% +/- 9.3%, p < 0.01), a trend toward a higher ED50 (dobutamine dosage rate causing half the maximum heart-rate response; median 16.8 microg/kg/min, p = 0.12) and a lower sigmoidicity factor determining the shape of the curve (median 2.1, p = 0.03).

CONCLUSION

The response to dobutamine exhibits wide interpatient variability, even in the absence of beta-blockade. Nonetheless, in the absence of beta-blockers, in most patients the dobutamine response reaches a plateau by the time the maximum infusion rate (40 microg/kg/min) is reached. Withdrawal of beta-blockers the evening before DSE may be inadequate time for elimination of beta-blocker effect, requiring the addition of atropine to achieve the desired response during DSE.

Safety and feasibility of dobutamine and dipyridamole stress echocardiography in hypertensive patients

OBJECTIVES

To establish whether safety and feasibility of dobutamine and dipyridamole stress echocardiography are affected by history of hypertension.

METHODS

Data on 2200 consecutive pharmacologic stress echocardiography (959 dobutamine and 1241 dipyridamole) performed between October 1990 and February 2001 at a single cardiology centre, were analysed.

RESULTS

There were two complications (1/480 tests) during dobutamine (one sustained ventricular tachycardia and one severe asthmatic attack following antidote administration) and two (1/620 tests) during dipyridamole (one non-Q wave myocardial infarction and one sustained ventricular tachycardia) stress. Complications or limiting side effects were observed in 83/959 patients (48/430 hypertensives and 35/529 normotensives) with dobutamine and in 34/1241 patients (17/571 hypertensives and 17/670 normotensives) with dipyridamole stress. Therefore, the overall feasibility was 88.8% in hypertensives and 93.4% in normotensives (P = 0.013) for dobutamine, and 97% in hypertensives and 97.5% in normotensives (P = 0.64) for dipyridamole. Dipyridamole was significantly more feasible than dobutamine in both hypertensive (P < 0.0001) and normotensive (P = 0.0006) subjects. Logistic regression analysis failed to identify clinical or echocardiographic predictors of adverse reactions with dipyridamole, while history of hypertension [odds ratio (OR) = 1.8, 95% confidence interval (CI) 1.1-2.8, P = 0.0138] was the only independent predictor of cumulative adverse reactions with dobutamine stress. In addition, history of hypertension (OR = 3.2, 95% CI, 1.2-8.5, P = 0.0166), resting wall motion abnormalities (OR = 1.8, 95% CI, 1.1-3.1, P = 0.0282), and age over 70 years (OR = 4.8, 95% CI, 1.5-15.3, P = 0.0087) predicted hypertensive response, ventricular tachycardia, and atrial fibrillation, respectively. No covariate was associated with hypotensive response during dobutamine test.

CONCLUSIONS

Dipyridamole has a slightly better safety profile and significantly higher feasibility than dobutamine stress both in hypertensives and in normotensives. In addition, the history of systemic hypertension is an independent predictor of cumulative adverse effects during dobutamine but not during dipyridamole stress.

Pharmacologic stress testing for coronary disease diagnosis: A meta-analysis

BACKGROUND

Although noninvasive pharmacologic stress tests are widely used, their relative performance is not clear. We compared the performance of pharmacologic stress tests combined with echocardiography or nuclear imaging for the diagnosis of coronary disease.

METHODS

We performed a regression meta-analysis of published data. We included studies published between January 1975 and June 1999 in which subjects underwent echocardiographic or single-photon emission computed tomography (SPECT) stress testing with adenosine, dipyridamole, or dobutamine for diagnosis of coronary artery disease. All subjects also underwent coronary angiography. Two independent reviewers abstracted population characteristics, technical factors, methodologic factors, and results and calculated test sensitivity and specificity.

RESULTS

Eighty-two studies met the inclusion criteria. The sensitivity of dipyridamole SPECT imaging, 89% (95% CI, 84%-93%), was higher than that of dipyridamole echocardiography, but the specificity of dipyridamole SPECT imaging, 65% (95% CI, 54%-74%), was lower than that of dipyridamole echocardiography. Dipyridamole and adenosine tests had similar sensitivities and specificities. The sensitivity of dobutamine echocardiography, 80% (95% CI, 77%-83%) was similar to that of dobutamine SPECT imaging, but dobutamine echocardiography had a higher specificity, 84% (95% CI, 80%-86%) than dobutamine SPECT imaging did.

CONCLUSIONS

The findings of our study can be used to guide the selection of the optimal pharmacologic stress test for each patient. Maximum sensitivity can be attained by use of a vasodilator combined with SPECT imaging. Maximum specificity can be attained by use of a vasodilator with echocardiography. The highest combination of sensitivity and specificity can be attained with dobutamine echocardiography.

Safety, feasibility, and diagnostic accuracy of accelerated high-dose dipyridamole stress echocardiography

Protocols for dipyridamole stress testing have evolved in the last 16 years in the neverending quest of optimal diagnostic accuracy and user friendliness. Higher dipyridamole dose in a shorter infusion time provides higher sensitivity, but concern over safety is still controversial. An accelerated high-dose (0.84 mg/kg in 6 minutes without atropine) dipyridamole stress test was performed on 1,295 patients in 2 echocardiographic laborotories: Institute of Clinical Physiology of Pisa and Niguarda Hospital of Milan. During testing, there were no deaths and no patients had ventricular fibrillation. Major adverse reactions occurred in 3 cases (1 every 431 studies): 1 myocardial infarction, 1 brief cardiac asystole, and 1 transient ischemic attack. Overall feasibility was 97%. In 66 patients with normal function at rest who were evaluated off therapy, with coronary angiography performed independently of test results, the accelerated high-dose protocol showed a sensitivity of 85% (confidence interval [CI] 73% to 92%) and a specificity of 93% (CI 83% to 97%) for angiographically assessed coronary artery disease (quantitatively assessed diameter reduction > or = 50%). Diagnostic accuracy of the accelerated high dose was 89% (CI 79% to 95%). Thus, accelerated high-dose dipyridamole stress echocardiography was reasonably safe and well tolerated. This protocol is especially appealing for its excellent diagnostic accuracy coupled with the short imaging time and no need for drug cocktails.

Dobutamine stress echocardiography: safety in diagnosing coronary artery disease

Dobutamine stress echocardiography is considered a relatively well-tolerated diagnostic modality, effective in the management of patients with known or suspected coronary artery disease. Adverse effects during testing are relatively frequent, precluding the achievement of a diagnostic end-point in about 5 to 10% of tests. These adverse effects, mostly tachyarrhythmias and arterial hypotension, are usually minor and self limiting. However, severe life-threatening complications, as well as death, also occur. By analysing Medline-quoted literature up to March 1999, we found 35 original studies from a single institution with more than 100 patients, as well as 2 multicentre studies, concerning the feasibility and safety of dobutamine stress echocardiography. In a cumulative total of 26438 tests performed, 79 life-threatening complications (such as acute myocardial infarction, asystole, ventricular fibrillation, sustained ventricular tachycardia or severe symptomatic hypotension) have been reported, giving an incidence of 1 severe adverse reaction per every 335 examinations. In addition, 29 isolated case reports have been published describing life-threatening complications during dobutamine echocardiography. In case reports, 2 deaths have been described, both due to acute cardiac rupture in patients with recent inferior myocardial infarction. Severe adverse reactions during dobutamine echocardiography can be ischaemia independent, and are independent of operator experience and are unpredictable; some complications can be late occurring and long lasting. As a consequence, the procedure must be clearly indicated, written informed consent has to be obtained from the patient, an attending physician must be present during testing, and long term observation of outpatients is useful in order to manage late complications. In conclusion, while the safety of dobutamine stress echocardiography was reported to be outstanding in early reports, further experience presents a substantially more worrying picture. This must be taken into account by both physicians and patients when assessing the risk-benefit profile of the procedure.

The comparable diagnostic accuracies of dobutamine-stress and dipyridamole-stress echocardiographies: a meta-analysis

BACKGROUND

Dobutamine-stress and dipyridamole-stress echocardiographies are widely used for pharmacological stress echocardiography, with wide geographical variations.

OBJECTIVE

To assess whether evidence derived from the literature indicates or disapproves that either stress modality confers diagnostic superiority.

METHODS

We performed a meta-analysis of peer-reviewed literature of published trials with head-to-head comparison, on the same population, of high-dose (0.84 mg/kg) dipyridamole-stress versus high-dose (up to 40 micrograms/kg per min) dobutamine-stress echocardiography. Data from 12 studies performed in 12 institutions in seven countries were analysed. Angiographic information about 818 patients was considered.

RESULTS

The diagnostic accuracies of the two tests were similar (631 of 818, 77%, for dipyridamole versus 654 of 818, 80%, for dobutamine, NS). Overall sensitivities were 403 of 568 (71%) for dipyridamole and 437 of 568 (77%) for dobutamine (P < 0.05). Sensitivities for patients with single-vessel disease were 177 of 275 (64%) for dipyridamole and 203 of 275 (74%) for dobutamine (P < 0.05). Sensitivities for patients with multivessel disease were 162 of 203 (80%) for dipyridamole and 163 of 203 (80%) for dobutamine (NS). Specificities were 232 of 250 (93%) for dipyridamole and 217 of 250 (87%) for dobutamine (P < 0.05). Data from an additional 26 studies with dipyridamole alone and 47 studies with dobutamine alone were analysed. The diagnostic accuracies were 80% for dipyridamole (n = 2038 patients; 95% confidence interval 75-82%) and 82% for dobutamine (n = 4264 patients; 95% confidence interval 79-84%).

CONCLUSION

High-dose dobutamine-stress and high-dose dipyridamole-stress echocardiographies have comparable diagnostic accuracies, with a slightly higher sensitivity with dobutamine and a slightly higher specificity with dipyridamole.

Prognostic value of pharmacological stress echocardiography in patients with known or suspected coronary artery disease: a prospective, large-scale, multicenter, head-to-head comparison between dipyridamole and dobutamine test. Echo-Persantine International Cooperative (EPIC) and Echo-Dobutamine International Cooperative (EDIC) Study Groups

OBJECTIVES

The study compared the prognostic value of dipyridamole and dobutamine stress echocardiography in patients with known or suspected coronary artery disease.

BACKGROUND

Extensive information is available on the relative diagnostic accuracy of the two tests assessed in a head-to-head fashion, whereas comparative data on their prognostic yield are largely preliminary to date.

METHODS

Dipyridamole (up to 0.84 mg/kg over 10 min) atropine (up to 1 mg over 4 min) (DIP) and dobutamine (up to 40 microg/kg/min)-atropine (1 mg over 4 min) (DOB) stress tests were performed in 460 patients with known or suspected coronary artery disease. Patients were followed up for 38+/-21 months.

RESULTS

The DIP was negative in 253 and positive in 207 patients. The DOB was negative in 242 and positive in 218 patients. During the follow-up, there were 80 cardiac events. For all cardiac events, the negative and positive predictive value were 83% and 17% for DOB, 84% and 19% for DIP, respectively (p = NS). Considering only cardiac death, by univariate analysis Wall-Motion Score Index (WMSI) at DIP peak dose (chi-square 13.80, p<0.0002) was the strongest predictor, followed by WMSI DOB (chi2 = 8.02, p<0.004) and WMSI at rest (chi2 = 6.85, p<0.008). By stepwise analysis, WMSI at DIP peak dose was the most important predictor (RR [relative risk] 7.4, p<0.0001).

CONCLUSIONS

In patients at low-to-moderate risk of cardiac events, pharmacological stress echocardiography with either dobutamine or dipyridamole allows effective and grossly comparable, risk stratification on the basis of the presence, severity and extension of the induced ischemia.

Pharmacologic stress echocardiography in the assessment of coronary artery disease

Pharmacologic stress echocardiography has gained widespread popularity in recent years because it is more feasible for the patient and less technically demanding for the echocardiographer than exercise stress testing. The two most popular pharmacologic stresses are dobutamine and dipyridamole. These agents provide similar prognostic value and diagnostic accuracy for angiographically assessed coronary artery disease; dobutamine has marginally higher sensitivity in single-vessel disease, and dipyridamole has marginally higher specificity in patients with normal coronary arteries. Both stresses are safe, but a physician should always be in attendance when they are administered: Life-threatening reactions can occur in one of 300 to 500 cases with dobutamine and in one of 700 to 1500 cases with dipyridamole. For dipyridamole and dobutamine echocardiography, outcome data are available from multicenter, international, observational, prospective studies, such as the EPIC (Echo Persantine International Cooperative) and EDIC (Echo Dobutamine International Cooperative).

Overall and Segmental Agreement of Stress Echocardiography

Several stress echocardiography (SE) modalities have been introduced for diagnosing coronary artery disease (CAD). Exercise and dobutamine SE are commonly considered to have a better diagnostic accuracy than vasodilator SE. The purpose of this study was to assess the agreement between the test results and the segmental concordance between three SE tests in patients with chest pain. A total of 60 patients (mean age, 55.1 years; SD, 2.1) were tested by symptom-limited bicycle (BSE), dipyridamole-atropine (DiASE), and dobutamine (DSE) tests. CAD (50% stenosis) was present in 44 patients, and 26 patients had one-vessel disease. In BSE and DSE, the double product at peak stress (26.5 and 16.1 vs 13.3 x 10(3), respectively, P < 0.005 vs DiASE) and the peak wall motion score index were higher than in DiASE (1.40 and 1.35 vs 1.26, respectively, P < 0.05 vs DiASE). BSE, DiASE, and DSE did not differ in sensitivity in diagnosing CAD (90%, 93%, and 95%, respectively). Similarly, there were no statistically significant differences in the diagnostic accuracy of BSE, DiASE, and DSE (78%, 88%, and 87%, respectively). The intermethod agreement was moderate between BSE and DiASE (kappa = 0.51), good between BSE and DSE (kappa = 0.62), and moderate between DiASE and DSE (kappa = 0.57). The segmental agreement between BSE, DiASE, and DSE was mostly moderate. Agreement was best between the pharmacologic tests due to test protocols, especially the anterior wall (kappa > 0.60). Also, the basal segments showed good agreement. In conclusion, BSE, DiASE, and DSE have a similar diagnostic accuracy in detecting CAD. The overall agreement between the tests was good, and the assessment of wall motion was variable. Nevertheless, concordant diagnosis of a patient can be obtained by BSE, DiASE, and DSE without loss of diagnostic power.

Dipyridamole stress echocardiography

Dipyridamole stress is the forerunner and prototype of pharmacological stress echo tests in the diagnosis of coronary artery disease. The safety of this test has been conclusively demonstrated as a result of extensive experience in large-scale multicenter projects. The diagnostic accuracy of dipyridamole stress echo is comparable to dobutamine and largely a function of the employed dose. Higher dosages (up to 0.84 mg/kg) are being required to achieve good sensitivity. The prognostic value has been shown to be independent and additive to clinical, exercise echocardiogram, and angiographic data. The test positive response should be titrated on the basis of severity, extent, and timing of induced dyssynergy with low positivity being associated to more anatomically and functionally severe forms of disease. Multicenter, randomized, prospective, international studies on cost-effectiveness directly comparing a noninvasive strategy centered on stress echo versus an invasive strategy centered on coronary angiography are currently ongoing.

Selection of the optimal stress test for the diagnosis of coronary artery disease

OBJECTIVE

To compare the value and limitations of exercise testing, dipyridamole echocardiography, dobutamine-atropine echocardiography, and MIBI-SPECT (technetium-99m methoxyisobutyl nitrile single photon emission computed tomography) during dobutamine infusion in the diagnosis of coronary artery disease.

DESIGN

The performance of these four tests was assessed in random order on a consecutive cohort of patients. The presence or absence of coronary artery disease was confirmed by coronary angiography.

SETTING

Two tertiary care and university centres.

PATIENTS

102 consecutive patients with chest pain and no previous history of coronary artery disease. Ten patients with left bundle branch block were excluded for further analysis of exercise testing and scintigraphy results.

RESULTS

MIBI-SPECT was the most sensitive (87%) but the least specific test (70%). Exercise stress testing had a sensitivity of 66%, which increased to 80% when patients with inconclusive results were excluded. Dipyridamole and dobutamine echocardiography had similar sensitivity (81%, 78%) and specificity (94%, 88%). All four tests had similar accuracy and positive and negative predictive values. Agreement between the echocardiographic techniques was excellent (detection of coronary artery disease 87%, kappa = 0.72; regional analysis 93%, kappa = 0.72; diagnosis of the "culprit" vessel 95%, kappa = 0.92), and it was good between echocardiographic techniques and MIBI-SPECT (diagnosis of the culprit vessel 90%, kappa = 0.84 with dobutamine and 92%, kappa = 0.85 with dipyridamole).

CONCLUSIONS

Exercise stress testing has a sensitivity comparable to other tests in patients capable of exercising and with no basal electrical abnormalities. The greatest sensitivity is offered by MIBI-SPECT and the greatest specificity is obtained with stress echocardiography. Redundant information is obtained with dipyridamole echocardiography, dobutamine echocardiography, and MIBI-SPECT.

Relative role of coronary stenosis severity and morphology in determining pharmacologic stress echo positivity

Angiographically assessed plaque morphology, not only plaque severity, may affect myocardial vulnerability to ischemia during stress testing. The aim of this study was to evaluate directly, in a head-to-head comparison, the relation between coronary stenosis severity and morphology and pharmacologic stress echo response. From our inpatients echo databank, we selected 68 patients (62 men, mean age 57 +/- 9 years) who had undergone high-dose dipyridamole and high-dose dobutamine-atropine echocardiography, performed within 1 week and in random order, before coronary angiography that showed significant coronary artery disease by selection. There were altogether 121 vessels with visually assessed stenosis >50% in 68 patients. Thirty-three had complex-type and 56 simple-type lesions (according to the Ambrose classification), whereas 32 vessels were occluded. During dobutamine echocardiography there were 51 dyssynergic regions of the left ventricle fed by different coronary arteries in 50 patients and dipyridamole stress was able to induce ischemia in 45 separate regions in 44 patients. The overall agreement between the 2 tests in recognizing ischemia was 76%. Induced ischemia was associated with greater quantitatively assessed stenosis severity for both dipyridamole (positive, 70 +/- 12% vs negative, 63 +/- 12% area reduction; p <0.05) and dobutamine (positive, 68 +/- 12% vs negative, 63 +/- 12% area reduction; p <0.05). The simple-type stenosis was more frequently identified with dobutamine (46%) versus dipyridamole (21%, [p <0.01]), whereas the complex-type stenosis was associated with a trend toward more frequent positivity of dipyridamole (55%) versus dobutamine (36%), p = 0.13. Adenosinergic stress positivity is affected not only by plaque severity, but also by plaque morphology, whereas adrenergic stress positivity is affected by plaque severity, not by plaque morphology.

[Elective noninvasive test in the diagnosis of coronary disease in the aged]

BACKGROUND AND PURPOSE

The purpose of this study was to determine the best noninvasive test to diagnose coronary artery disease in the elderly. PATTERNS AND METHODS: We conducted a study on 56 elderly patients (> 65 years) with chest pain and no previous history of coronary artery disease. They underwent exercise stress test, dipyridamole echocardiography (0.84 mg/kg), dobutamine echocardiography (up to a total dose of 40 microgram/kg/min and atropine when it was necessary), dobutamine MIBI-SPECT and coronary angiography.

RESULTS

Angiography detected significant coronary artery disease in 41 patients. All tests used in this study had a similar sensitivity (conclusive exercise stress test 87%, dipyridamole echocardiography 83%, dobutamine echocardiography 80% and MIBI-SPECT 87%; p = NS). Coronary angiography did not identify significant lesions in 15 patients. Specificity of conclusive exercise stress test, dipyridamole and dobutamine echocardiography was similar (75%, 100% and 93% respectively; p = NS). However, the specificity of stress echocardiography was higher than that of scintigraphy (100% vs 66%; p = 0.02 for dipyridamole echocardiography and 93% vs 66%; p = 0.07 for dobutamine echocardiography). Diagnostic accuracy of each test was similar.

CONCLUSIONS

Exercise stress test remains the non invasive diagnostic test of choice to detect coronary disease in the elderly. If this test is inconclusive, both stress echocardiography and isotopic studies are useful, although the specificity of stress echocardiography is higher than that of scintigraphy.